A considerable number of practice torpedoes are used for exercise purposes. A torpedo is designed to surface after it has made its run so that it can be retrieved and utilized again for other practice exercises. However, locating practice torpedoes at sea is often a difficult task. If an expended torpedo cannot be located within a specific period of time, it must be scuttled by use of a scuttle valve to prevent it from becoming a hazard to shipping.
One type of scuttle valve described in U.S. Pat. No. 3,763,512 utilizes an outwardly ejecting piston. The piston is jettisoned from a hull, enabling ocean water to enter, and cause the vessel to become negatively buoyant and sink. However, hydrostatic pressure can inhibit effective ejection of the piston. External hull damage or ocean borne debris can prevent ejection. Outwardly ejecting pistons pose a risk of serious bodily injury to persons involved in the manufacture, transport, and handling of torpedoes utilizing this type of scuttle valve if the piston ejects prematurely.
Another type of scuttle device uses soluble plugs as described in U.S. Pat. Nos. 3,308,046 and 3,605,416. This type of plug is made of a sacrificial metal such as magnesium or aluminum and is used to provide a watertight seal. The plugs chemically react when exposed to sea water and are destroyed, allowing sea water to enter and sink a vessel.
Thus there is a continuing need to improve the state of the art to develop a scuttle valve that is inherently reliable and does not pose a hazard to associated personnel.